This disclosure relates to methods of making composite laminates and, in particular, to improvements in the infusion of resin material in a fabric preform during resin transfer molding.
Large composite parts are often manufactured using a process called vacuum-assisted resin transfer molding (VARTM). Conventionally, plies of a dry fabric or fiber are first applied over a mold or tool surface to form a preform or lay up of a desired shape and thickness. With the preform having been formed over the tool, a flexible, gas impervious bag (i.e., a sheet or a film) is then placed over the preform and a vacuum is drawn between the mold and the bag. The vacuum draws the bag against the preform to compress the preform. An activated or catalyzed resin is then supplied into the volume of the preform between the bag and the old through an injection port. The vacuum slowly draws the resin through the preform (which is not fully dense as it is fibrous) so that the preform is fully infused with the resin. The resin is then cured with time and/or heat, so as to form the final composite part.